245 research outputs found
HD 213258: a new rapidly oscillating, super-slowly rotating, strongly magnetic Ap star in a spectroscopic binary
We report about HD 213258, an Ap star that we recently identified as
presenting a unique combination of rare, remarkable properties. Our study of
this star is based on ESPaDOnS Stokes I and V data obtained at 7 epochs
spanning a time interval slightly shorter than 2 years, on TESS data, and on
radial velocity measurements from the CORAVEL data base. We confirm that HD
213258 is definitely an Ap star. We found that, in its spectrum, the Fe II
{\lambda}6149.2 {\AA} line is resolved into its two magnetically split
components. The mean magnetic field modulus of HD 213258, ~ 3.8 kG does not
show significant variations over ~2 years. Comparing our mean longitudinal
field determinations with a couple of measurements from the literature, we show
that the stellar rotation period must likely be of the order of 50 years, with
a reversal of the field polarity. Moreover, HD 213258 is a rapidly oscillating
Ap (roAp) star, in which high overtone pulsations with a period of 7.58 min are
detected. Finally, we confirm that HD 213258 has a mean radial velocity
exceeding (in absolute value) that of at least 99% of the Ap stars. The radial
velocity shows low amplitude variations, which suggests that the star is a
single-line spectroscopic binary. It is also a known astrometric binary. While
its orbital elements remain to be determined, its orbital period likely is one
of the shortest known for a binary roAp star. Its secondary is close to the
borderline between stellar and substellar objects. There is a significant
probability that it may be a brown dwarf. While most of the above-mentioned
properties, taken in isolation, are observed in a small fraction of the whole
population of Ap stars, the probability that a single star possesses all of
them is extremely low. This makes HD 213258 an exceptionally interesting object
that deserves to be studied in detail in the future.Comment: Accepted for publication in A&A; 6 pages, 4 figure
The economic importance of the Belgian ports: Flemish maritime ports, Liège port complex and the port of Brussels – Report 2016. National Bank of Belgium Working Paper No. 342
This Working Paper analyses the economic importance of the Belgian ports based largely on
the annual accounts data for the year 2016. As the years prior to 2016 have been described in
earlier papers in the same series, we mainly focus on the figures for 2016 and developments
between 2015 and 2016.
On the back of strong growth, direct value added in the Belgian ports remained more or less
stable in 2016 at around € 18 000 million (current prices) or roughly 4.3% of Belgium’s GDP. Direct
value added declined in the Flemish seaports, mainly in the port of Antwerp. Ghent and Zeebrugge
could only partly compensate for the fall in Antwerp’s value added, while Ostend showed a small
decline itself. The inland ports as a whole grew over the period 2015-2016; the port of Brussels
registered a decline and the Liège port complex an increase. Indirect value added is around 82% of
the direct figure.
After declining from 2012, direct employment in the Belgian ports was more or less stable in
2016 at around 115 000 FTE or approximately 2.8% of Belgium’s total domestic employment. Direct
employment in the Flemish seaports increased, mainly in the ports of Zeebrugge, Ghent and
Antwerp. Ostend showed a decline in employment. The inland ports recorded lower employment;
the port of Brussels registered a decline, as did the Liège port complex. Indirect employment is
around 1.2 times the direct figure.
Delving deeper into the data and trying to explain the above trends in terms of the structural
composition of the Belgian ports shows that all ports are concentrated on a few sectors, and within
those sectors often on just a handful of companies.
Based on the figures of the traffic, the Flemish ports can be considered as real bridgeheads
for trade with the UK. Developments regarding the modalities and consequences of the Brexit
therefor should be followed with the greatest attention. Given the existing import and export
volumes in terms of tonnage, it seems it will mostly be a challenge in Zeebrugge and to some extent
for Antwerp
L'évaluation structurée des forces des jeunes : qu'en pense le personnel psychosocial en milieu de placement ?
peer reviewedAssessment and intervention with justice-involved youth is a central concern of juvenile justice. Several countries use risk assessment tools to predict the reoffending risk more accurately and to intervene appropriately with youths (Bonta & al., 2008; Koehler & al., 2013; Miller & Maloney, 2013). The emphasis is set on risk, leaving less place for consideration of the positive aspects of youths (Case & Haines, 2016; McNeill, 2006).
In French-speaking Belgium, the University of Liège has been working on integrating strengths alongside risk factors in the justice-involved youth assessment within the Strengths/Structured Assessment for Youth (S/SAY), taking the form of a structured assessment instrument. A strength references to « a skill, attitude, exploited or not, present within each individual or his community at large, which can potentially be mobilized in order to adopt a pro-social behavior, to improve his well-being, while reducing the likelihood of harming others or oneself » (Miny, 2020, p.9). The innovative characteristic of the strength concept is its difference with the protection factor in that it offers a primary vision of justice-involved youth’s positive side. Strengths precede protection factors because they don’t play yet protective effect. Recent research into the implementation of risk/needs assessment instruments has revealed that probation officers are reappropriating evidence-based practice guidelines (Viglione, 2019; Viglione & al., 2018). This observation highlights the need to examine the perception of social workers in addition to studies on psychometric properties. In consequence, the social validity (Schwartz & Baer, 1991) of a new assessment tool appears essential.
Nine semi-structured interviews with Belgian social workers (77.78% female and 22.22% male, average age 36.56) who use S/SAY in three youth justice facilities will be presented. A thematic analysis following the principles of Miles & Huberman (2019) was carried out and a thematic tree will be developed.
70% of these social workers have already experience in justice-involved youth but no previous use of structured assessment instrument.
Since the formal inclusion of strengths, they recognize the usefulness of the structured assessment, beside their clinical judgment, to gain in objectivity. Moreover, they pointed out the relevance of the evaluation of the strengths as concrete skills of the youth. They link the formal identification of these strengths to an engine of change for youth. These preliminary results encourage further inclusion of the youths’ positive aspects within the actuarial assessment.
In conclusion, a fair and accurate assessment of the justice-involved youths’ strengths, through an innovative tool, is an important issue both from a safety society and from the youth desistance. The way social workers perceive and use a tool to assess their strengths will have a direct impact on the quality of treatment and the positive effects expected
Simultaneous multicurve approximation with NURBS
info:eu-repo/semantics/publishe
Pushing the limit of instrument capabilities
Chemically Peculiar (CP) stars have been the subject of systematic research for more than 50 years. With the discovery of pulsation of some of the cool CP stars, and the availability of advanced spectropolarimetric instrumentation and high signal-to-noise, high resolution spectroscopy, a new era of CP star research emerged about 20 years ago. Together with the success in ground-based observations, new space projects are developed that will greatly benefit future investigations of these unique objects. In this contribution we will give an overview of some interesting results obtained recently from ground-based observations and discuss the future outstanding Gaia space mission and its impact on CP star researc
Pushing the limit of instrument capabilities
Chemically Peculiar (CP) stars have been subject of systematic research since
more than 50 years. With the discovery of pulsation of some of the cool CP
stars, the availability of advanced spectropolarimetric instrumentation and
high signal- to-noise, high resolution spectroscopy, a new era of CP star
research emerged about 20 years ago. Together with the success in ground-based
observations, new space projects are developed that will greatly benefit for
future investigations of these unique objects. In this contribution we will
give an overview of some interesting results obtained recently from
ground-based observations and discuss on future outstanding Gaia space mission
and its impact on CP star research.Comment: Joint Discussion 04, Secsion 1, To appear in Highlights of Astronomy,
Proc. of the XXVIIth IAU General Assembly, Rio de Janeiro, Brazil, August
2009, 9 page
Measurement of the cosmic ray spectrum above eV using inclined events detected with the Pierre Auger Observatory
A measurement of the cosmic-ray spectrum for energies exceeding
eV is presented, which is based on the analysis of showers
with zenith angles greater than detected with the Pierre Auger
Observatory between 1 January 2004 and 31 December 2013. The measured spectrum
confirms a flux suppression at the highest energies. Above
eV, the "ankle", the flux can be described by a power law with
index followed by
a smooth suppression region. For the energy () at which the
spectral flux has fallen to one-half of its extrapolated value in the absence
of suppression, we find
eV.Comment: Replaced with published version. Added journal reference and DO
Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory
The Auger Engineering Radio Array (AERA) is part of the Pierre Auger
Observatory and is used to detect the radio emission of cosmic-ray air showers.
These observations are compared to the data of the surface detector stations of
the Observatory, which provide well-calibrated information on the cosmic-ray
energies and arrival directions. The response of the radio stations in the 30
to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of
the incoming electric field. For the latter, the energy deposit per area is
determined from the radio pulses at each observer position and is interpolated
using a two-dimensional function that takes into account signal asymmetries due
to interference between the geomagnetic and charge-excess emission components.
The spatial integral over the signal distribution gives a direct measurement of
the energy transferred from the primary cosmic ray into radio emission in the
AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air
shower arriving perpendicularly to the geomagnetic field. This radiation energy
-- corrected for geometrical effects -- is used as a cosmic-ray energy
estimator. Performing an absolute energy calibration against the
surface-detector information, we observe that this radio-energy estimator
scales quadratically with the cosmic-ray energy as expected for coherent
emission. We find an energy resolution of the radio reconstruction of 22% for
the data set and 17% for a high-quality subset containing only events with at
least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO
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